Car M was driving on a highway at a constant speed of 50 miles per hou

Question

Car M was driving on a highway at a constant speed of 50 miles per hour. If Car N was 3 miles behind Car M 20 minutes ago and 2 miles ahead of Car M 5 minutes ago, what was the speed of Car N? Assume that Car N was driving at a constant speed.

A. 60 miles per hour
B. 70 miles per hour
C. 90 miles per hour
D. 100 miles per hour
E. 110 miles per hour

A. 60 miles per hour
B. 70 miles per hour
C. 90 miles per hour
D. 100 miles per hour
E. 110 miles per hour

nick1816 · Accepted Answer

Relative distance covered by N with respect to M= 3+2=5
Time taken=15 minutes or 0.25 hours
Relative speed of N with respect to M= 5/0.25=20

Speed of N= 50+20= 70mph

Eternal · Answer

In 15 min car M traveled= 50/4= 12.5 kms

In the same 15 min car N traveled= 3 kms (behind) + 12.5 kms (needed to be at the same point as M) + 2 kms (ahead)= 17.5 kms

So the speed of car N will be 17.5 * 4 = 70 km/h Answer.

TestPrepUnlimited · Answer

If we treat Car M as a stationary object, Car N moved 5 miles in 15 minutes and its speed relative to M would be +20 mi/h. Since M is traveling at 50 mi/h, Car N is faster by 20 mi/h so it is traveling 70 mi/h. Therefore the answer is C.

ScottTargetTestPrep · Answer

We see that car N gains 2 - (-3) = 5 miles on car M in 20 - 5 = 15 minutes = 1/4 hour, so car N must be 5/(1/4) = 20 miles per hour faster than car M. Since car M is moving at 50 mph, car N must be moving at 70 mph.

Answer: B

Ahi · Answer

Let the speed of car n is v miles /hr

a/c to question,

speed of car m is 50 miles/hr.

car n was 3 miles behind car m 20 minutes ago and 2 miles ahead of car m 5 minutes ago.

during 15 minutes , relative distance of car n becomes (3 + 2) = 5miles.

so, relative distance = relative velocity × time taken

or, 5 miles = velocity of car n with respect to car m × 15 min

or, 5miles = (v - 50miles/hr) × 15/60 hr

or, 5 = (v - 50) × 1/4

or, 20 = v - 50

or, v = 20 + 50 = 70 miles/hr

hence, speed of car n is 70 miles/hr

DrHuber · Answer

To solve this problem, we need to use the formula: distance = rate x time. Let's call the speed of Car N "r".

From the information given, we know that 20 minutes ago, Car M and Car N were 3 miles apart. In 20 minutes, Car M traveled (20/60) x 50 = 16.67 miles. So, Car N traveled (16.67 + 3) miles in 20 minutes.
Similarly, we know that 5 minutes ago, Car M and Car N were 2 miles apart. In 5 minutes, Car M traveled (5/60) x 50 = 4.17 miles. So, Car N traveled (4.17 - 2) miles in 5 minutes.

Now, we can set up two equations:
(16.67 + 3) = r x (1/3) (20 minutes is 1/3 of an hour) (4.17 - 2) = r x (1/12) (5 minutes is 1/12 of an hour)

Simplifying these equations, we get:
r = 70 miles per hour

Therefore, the speed of Car N was 70 miles per hour. The correct answer is (B).

saynchalk · Answer

Can someone solve this using the basic formula for T/S/D

Car M was driving on a highway at a constant speed of 50 miles per hou

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Car M was driving on a highway at a constant speed of 50 miles per hou

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

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